JP2005293968A - Manufacturing method of organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic electroluminescent element capable of improving production efficiency and mass productivity while preventing deterioration of a characteristic of an organic material. <P>SOLUTION: A plurality of crucibles 10, 11 and 12 are so arranged as to face to a surface of a substrate 50 intended to form an organic layer thereon. The plurality of crucibles 10, 11 and 12 are arranged in parallel with one another under the substrate 50. The plurality of crucibles 10, 11 and 12 each have an elongated box-like shape extending in the Y-direction. A projecting part extending in the Y-direction is formed on each upper surface of the plurality of crucibles 10, and a plurality of organic material spouting holes 20, 21 and 22 are formed on the upper surfaces of the projecting parts. The plurality of organic material spouting holes 20, 21 and 22 are slantingly formed so as to be able to spout the organic material to spouting target points. The crucibles 11 and 12 are filled with the same organic material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an organic electroluminescence element.

  In recent years, with the diversification of information equipment, there has been an increasing need for flat display elements that consume less power than commonly used CRTs (cathode ray tubes). As one of such flat display elements, an organic electroluminescence (hereinafter abbreviated as organic EL) element having features such as high efficiency, thinness, light weight, and low viewing angle dependency has been attracting attention. Research and development of the display used is being actively conducted.

  The organic EL element injects electrons and holes from the electron injection electrode and the hole injection electrode into the light emitting part, recombines the injected electrons and holes at the emission center to bring the organic molecules into an excited state, and the organic molecules Is a self-luminous element that emits fluorescence when it returns from the excited state to the ground state. This organic EL element can change a luminescent color by selecting the fluorescent material which is a luminescent material, and the expectation for the application to display apparatuses, such as multi-color and a full color, is increasing.

In general, each layer of the organic EL element is formed using a vapor deposition method. In this vapor deposition method, first, the crucible is filled with an organic material, and the organic material is evaporated by heating the organic material in the crucible with a heater provided outside the crucible, thereby forming an organic layer on the substrate. is there.
JP 2001-247959 A JP 2003-293122 A

  However, the organic material filled in the crucible may be deteriorated in characteristics of the organic material when heated by a heater. In order to prevent this deterioration, the heating temperature by the heater can be lowered. However, when the heating temperature is lowered, the deposition rate is lowered. Thereby, the production efficiency in the manufacture of the organic EL element is lowered.

  The objective of this invention is providing the manufacturing method of the organic electroluminescent element which can improve production efficiency and mass productivity, preventing the deterioration of the characteristic of an organic material.

  The manufacturing method of the organic electroluminescent element which concerns on this invention is a manufacturing method of the organic electroluminescent element provided with the organic layer which consists of organic materials on a board | substrate, Comprising: The plurality extended in the 1st direction and arrange | positioned substantially in parallel A step of filling at least two of the crucibles with the same organic material, a step of heating the two crucibles, and a second direction crossing the plurality of crucibles and the substrate relative to each other in the first direction And a step of moving to the position.

  In the method for manufacturing an organic electroluminescent element according to the present invention, at least two crucibles extending in the first direction and arranged substantially in parallel are filled with the same organic material. While the two crucibles are heated, the plurality of crucibles and the substrate are moved relative to each other in a second direction that intersects the first direction. Thereby, an organic layer can be uniformly formed on the entire surface of the substrate.

  In this case, since the same organic material is filled in at least two crucibles, even when the heating temperature of the crucible is lowered, the evaporation of the organic material is compared with the case where the heating temperature is set high using one crucible. The amount can be kept equal. As a result, it is possible to improve the production efficiency and mass productivity of the organic electroluminescence element while preventing the deterioration of the characteristics of the organic material.

  The plurality of crucibles are configured such that the spray direction of at least two crucibles is set so that the vapor of the organic material is sprayed with a predetermined spread around the set spray direction, and the organic material is deposited on a common region of the substrate. Also good.

  In this case, since the organic material can be ejected from at least two crucibles to the common region of the substrate, the thickness of the organic layer formed on the substrate can be controlled uniformly.

  The organic material may include a rubrene-based material. Here, the rubrene-based organic material is easily deteriorated by heat. In this case, since the heating temperature to the organic material can be lowered, deterioration of the characteristics of the rubrene-based material can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the production efficiency and mass productivity of an organic electroluminescent element can be improved, preventing the deterioration of the characteristic of an organic material.

  Hereinafter, the manufacturing method of the organic electroluminescence element according to the present embodiment will be described.

  FIG. 1 is a perspective view for explaining a method of manufacturing an organic electroluminescence element according to an embodiment of the present invention. Hereinafter, the organic electroluminescence element is abbreviated as an organic EL element.

  In FIG. 1, three directions orthogonal to each other are defined as an X direction, a Y direction, and a Z direction. The X direction and the Y direction are directions parallel to the surface of the substrate 50 forming the organic layer, and the Z direction is a direction perpendicular to the surface of the substrate 50.

  As shown in FIG. 1, a plurality of crucibles 10, 11, and 12 are used in the method for manufacturing an organic EL element according to the present embodiment. The plurality of crucibles 10, 11, and 12 are arranged to face the surface of the substrate 50 on which the organic layer is to be formed. In FIG. 1, a plurality of crucibles 10, 11, 12 are arranged in parallel below the substrate 50.

  As shown in FIG. 1, the plurality of crucibles 10, 11, and 12 have an elongated box shape extending in the Y direction. Convex portions extending in the Y direction are formed on the top surfaces of the plurality of crucibles 10, and a plurality of organic material ejection holes 20 are formed on the top surfaces of the convex portions. Similarly, in the crucibles 11 and 12, a convex portion extending in the Y direction is formed on the upper surface, and a plurality of organic material ejection holes 21 and 22 are formed on the upper surface of the convex portion.

  Next, FIG. 2 is a schematic cross-sectional view for explaining the organic material ejection hole 20 formed in the convex portion of the crucible 10 in FIG. 1, and FIG. 3 is formed in the convex portion of the crucible 11 in FIG. FIG. 4 is a schematic cross-sectional view for explaining the organic material ejection hole 21, and FIG. 4 is a schematic cross-sectional view for explaining the organic material ejection hole 22 formed in the convex portion of the crucible 12.

  As shown in FIG. 2, the crucible 10 is composed of a U-shaped container 1, and a lid 2 having an organic material ejection hole 20 is formed in the opening of the container 1. The container 1 and the lid part 2 may be formed integrally or may be formed as separate bodies. The organic material ejection hole 20 formed in the lid 2 ejects the organic material in the range of the spread angle θ1 with the ejection direction 30 toward the ejection target point P as the center. Here, the ejection target point P indicates the center point of the region where the organic material is evaporated or sublimated from the crucible 10 and deposited on the substrate 50. The organic material ejection hole 20 formed in the lid 2 is provided such that the ejection direction 30 is inclined by an angle θ10 with respect to the Z axis.

  Similarly, the crucible 11 shown in FIG. 3 includes a U-shaped container 1, and a lid 2 a having an organic material ejection hole 21 is formed in the opening of the container 1. The organic material ejection hole 21 formed in the lid portion 2a ejects the organic material in the range of the spread angle θ1 with the ejection direction 30 toward the ejection target point P as the center. Further, the organic material ejection holes 21 formed in the lid portion 2 a are provided with the ejection direction 30 parallel to the Z axis, that is, perpendicular to the substrate 50.

  Further, the crucible 12 shown in FIG. 4 is composed of a U-shaped container 1, and a lid 2 b having an organic material ejection hole 22 is formed in the opening of the container 1. The organic material ejection hole 22 formed in the lid portion 2b ejects the organic material in the range of the spread angle θ1 with the ejection direction 30 toward the ejection target point P as the center. Further, the organic material ejection holes 22 formed in the lid 2b are provided such that the ejection direction 30 is inclined by an angle −θ12 with respect to the Z axis.

  Next, FIG. 5 is a schematic diagram showing the positional relationship between the substrate 50 of FIG. 1 and the plurality of crucibles 10, 11, 12.

  As shown in FIG. 5, the target ejection point P indicates the center point of the length L1 of the region of the organic material deposited by the crucibles 10, 11, and 12. The angles θ10 and θ12 described above are determined by the position of the target ejection point P, the distance H between the substrate 50 and the crucibles 10, 11, and 12, the distance L3 between the crucible 10 and the crucible 11, and the distance L4 between the crucible 11 and the crucible 12. Is done.

  Therefore, by setting the angles θ10 and θ12 to optimum values, the organic material ejected from the crucibles 10, 11, and 12 is uniformly deposited in the common region of the substrate 50.

  Next, a method for forming an organic layer on the surface of the substrate 50 will be described.

  First, an organic material is filled in the crucibles 10, 11, and 12 shown in FIGS. 2, 3, and 4 (not shown). Here, for example, the crucible 11 and the crucible 12 are filled with the same organic material. Details of the organic material to be filled will be described later.

  Next, the crucibles 10, 11 and 12 are heated by heaters (not shown) provided in the crucibles 10, 11 and 12. The organic material filled in the crucibles 10, 11 and 12 is evaporated or sublimated by the heat.

  At this time, the crucibles 10, 11, and 12 reciprocate in the X direction at a constant speed with respect to the substrate 50. The moving speed is preferably 5 mm / sec or more and 10 mm / sec or less. Thereby, the evaporated or sublimated organic material is uniformly deposited on the substrate 50, and an organic layer is formed on the surface of the substrate 50.

  In this case, since the crucibles 11 and 12 are filled with the same organic material, the evaporation of the organic material can be achieved even when the heating temperature of the heater is lowered as compared with the case where the heating temperature is set higher using one crucible. The amount can be kept equal. As a result, it is possible to improve the production efficiency and mass productivity of the organic electroluminescence element while preventing the deterioration of the characteristics of the organic material.

  In the present embodiment, the crucibles 10, 11, and 12 are moved at a constant speed with respect to the substrate 50. However, the present invention is not limited to this, and the crucibles 10, 11, and 12 are moved at a constant speed only in one direction. The crucibles 10, 11, and 12 may be moved and stopped intermittently.

  Furthermore, in this embodiment, the crucibles 10, 11, and 12 are moved. However, the present invention is not limited to this, and the substrate 50 may be moved while the crucibles 10, 11, and 12 are fixed. .

  Next, FIG. 6 is a schematic structural diagram of an organic EL element formed by the manufacturing method according to the present embodiment.

  As shown in FIG. 6, the organic EL element 600 includes a substrate 50, an anode (hole injection electrode) 51, a hole injection layer 52, a hole transport layer 53, a light emitting layer 54, an electron transport layer 55, and a cathode (electron injection electrode) 56. In order.

A transparent anode 51 is formed on the substrate 50. As the material of the anode 51, indium tin oxide (hereinafter abbreviated as ITO) is used. In addition to ITO, tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), or the like is used. A hole injection layer 52 made of an organic material and a hole transport layer 53 made of an organic material are formed so as to cover the anode 51.

  As a material for the hole injection layer 52, 4,4'4 "-tris (N- (2-naphthyl) -N-phenyl-amino) -triphenylamine (4,4) having a molecular structure represented by the following formula (1): 4'4 "-Tris (N- (2-naphthyl) -N-phenyl-amino) -triphenylamine (hereinafter abbreviated as 2TNATA) or the like is used.

  Further, as a material of the hole transport layer 53, N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine (N, N′-) having a molecular structure represented by the following formula (2) Di (naphthalene-1-yl) -N, N′-diphenyl-benzidine (hereinafter abbreviated as NPB) and the like are used.

  A light emitting layer 54 made of an organic material is formed on the hole transport layer 53. As a material of the light emitting layer 54, NPB which is a host material and has a molecular structure represented by the above formula (2), and 5,12-bis (4- (4- () having a molecular structure represented by the following formula (3) as a light emitting dopant. 6-methylbenzothiazol-2-yl) phenyl) -6,11-diphenylnaphthacene (5,12-Bis (4- (6-methylbenzothiazol-2-yl) phenyl) -6,11-diphenylnaphthacene: DBzR) For example). Here, DBzR is a rubrene derivative (rubrene-based material).

  Further, an electron transport layer 55 is formed on the light emitting layer 54. As a material of the electron transport layer 55, tris (8-hydroxyquinolinato) aluminum (hereinafter abbreviated as Alq) having a molecular structure represented by the formula (4) is used.

  Further, as the material of the cathode 56, an MgIn alloy (ratio 10: 1) or the like is used.

  The crucibles 10, 11, and 12 are used for forming the light emitting layer 54 of the organic EL element 600 described above. In this case, the crucible 10 is filled with NPB, and the crucibles 11 and 12 are filled with DBzR. Here, the rubrene-based organic material is easily deteriorated by heat.

  In this case, since the crucibles 11 and 12 are filled with the same rubrene-based organic material (DBzR), even when the heating temperature of the heater is lowered, the heating temperature is set higher using one crucible. Thus, the evaporation amount of the rubrene-based organic material can be maintained at the same level. As a result, the production efficiency and mass productivity of the organic electroluminescence element can be improved while preventing the deterioration of the characteristics of the rubrene-based material.

  In the present embodiment, the back-emission structure organic EL element 600 that extracts light from the anode 51 has been described. However, the present invention is not limited to this, and the present invention is applicable to a top-emission structure organic EL element that extracts light from the cathode 56 side. It can also be applied to an element.

  Furthermore, although the case where crucibles 10, 11, and 12 are used has been described in the present embodiment, the present invention is not limited to this, and any plurality of crucibles may be used.

  In the present embodiment, the organic material ejection hole 20 of the crucible 10 and the organic material ejection hole 22 of the crucible 12 are inclined by the angles θ10 and θ12. However, the present invention is not limited to this, and the crucible 10 and the crucible 12 itself. May be inclined at angles θ10 and θ12.

(Other examples of positional relationship between substrate and multiple crucibles)
Next, an example in which the crucible 13 is used instead of the crucible 10 will be described as another configuration example of the positional relationship between the substrate 50 and the plurality of crucibles 10, 11, and 12.
FIG. 7 is a schematic cross-sectional view of the crucible 13, and FIG. 8 is a schematic view showing the positional relationship between the substrate 50 and the plurality of crucibles 11, 12 and 13.

  7 and 8, three directions orthogonal to each other are defined as an X direction, a Y direction, and a Z direction. The X direction and the Y direction are directions parallel to the surface of the substrate 50 forming the organic layer, and the Z direction is a direction perpendicular to the surface of the substrate 50.

  As shown in FIG. 7, the crucible 13 includes a U-shaped container 1, and a lid 2 c having an organic material ejection hole 23 is formed in the opening of the container 1. The organic material ejection hole 23 formed in the lid portion 2c ejects the organic material with respect to the ejection target point P within the range of the spread angle θ1. In addition, the organic material ejection hole 23 formed in the lid 2c is provided to be inclined by an angle −θ13 with respect to the Z axis.

  Next, as shown in FIG. 8, the target ejection point P indicates the center point of the length L1 of the region of the organic material deposited by the crucibles 11, 12 and 13. The angles θ12 and θ13 described above are determined by the position of the target ejection point P, the distance H between the substrate 50 and the crucibles 11, 12, and 13, the distance L4 between the crucible 11 and the crucible 12, and the distance L5 between the crucible 12 and the crucible 13. Is done.

  Therefore, by setting θ12 and θ13 to optimum values, the organic material ejected from the crucibles 11, 12, and 13 is uniformly deposited in the common region of the substrate 50.

  Hereinafter, in the examples, the organic EL element shown in FIG. 6 was manufactured using the method for manufacturing the organic EL element according to the present embodiment. Moreover, in the comparative example, the organic EL element was produced using the manufacturing method of the conventional organic EL element. Details of the examples and comparative examples will be described below.

(Example)
In the example, the substrate 50 having a size of 500 mm × 350 mm was used. The plurality of crucibles 10, 11 and 12 were provided at positions 200 mm below the substrate 50.

  In the embodiment, the distance L3 between the crucible 10 and the crucible 11 is 100 mm, the distance L4 between the crucible 11 and the crucible 12 is 100 mm, the length L2 in the X direction of the substrate 50 is 500 mm, the angle θ10 of the crucible 10 is 45 degrees, The angle θ12 of the crucible 12 was −45 degrees. The region length L1 is 400 mm.

  First, the anode 51 was formed on the glass substrate 50 by sputtering. The substrate 50 on which the anode 51 was formed was washed with a neutral detergent and pure water, and then baked at a predetermined temperature for a predetermined time. Thereafter, UV / 03 cleaning was performed, and the vacuum deposition apparatus was set in a vacuum.

  Next, 2TNATA was filled in a crucible (not shown). Then, the hole injection layer 52 was formed on the anode 51 by heating the crucible. Next, NPB was filled inside the crucible (not shown). Then, the hole transport layer 53 was formed on the hole injection layer 52 by heating the crucible.

  Subsequently, NPB as a host material was filled into the crucible 10 of FIG. 1, and DBzR as a red light emitting dopant was filled into the crucibles 11 and 12.

  Then, the crucibles 10, 11 and 12 were heated by a heater while moving in one direction (X direction) at a constant speed (10 mm / sec). In the example, the heating temperature by the heater was set to about 320 ° C. Then, a light emitting layer 54 was formed on the hole transport layer 53.

  Next, Alq was filled in the crucible (not shown). And the electron carrying layer 55 was formed on the light emitting layer 54 by heating a crucible. Furthermore, Al was formed as a cathode to produce an organic EL element.

(Comparative example)
In the comparative example, at the time of forming the light emitting layer, the crucible 10 was filled with NPB as a host material, and the crucible 11 was filled with DBzR as a red light emitting dopant. In this case, the crucible 12 is not used.

  Moreover, the heating temperature by a heater was set to 340 degreeC. About other conditions, it carried out similarly to the Example, and produced the organic EL element.

(Evaluation)
Luminous efficiency, CIE (Comission International d'Eclairage) chromaticity coordinates CIE, driving voltage, and luminance half-life of the organic EL devices produced in Examples and Comparative Examples were measured. The measurement results are shown in Table 1.

  In Table 1, the measurement results of the characteristics of the organic EL elements of Examples and Comparative Examples were normalized with each measurement result of the Comparative Example as 1, and each measurement result normalized was shown.

  X is the horizontal axis of the CIE chromaticity coordinates, and y is the vertical axis of the CIE chromaticity coordinates.

  As shown in Table 1, the luminous efficiency of the organic EL element produced in the example was 2.14 times that of the organic EL element produced in the comparative example.

  Moreover, in the organic EL element produced by the comparative example, the light of the target chromaticity was not generated by deterioration of the organic material which comprises an organic EL element. On the other hand, in the organic EL device produced in the example, light having a target chromaticity was generated.

  The drive voltage of the organic EL element produced in the example was 1.05 times the drive voltage of the organic EL element produced in the comparative example.

  Moreover, the luminance half-life of the organic EL device produced in the example was 10 times the luminance half-life of the organic EL device produced in the comparative example.

  When the crucibles 11 and 12 are filled with the same organic material and the heating temperature of the crucibles 11 and 12 is set low, the crucibles 11 and 12 are filled with the organic material and the crucible heating temperature is set high. Compared with, the light emission characteristics of the organic EL element were improved.

  The present invention can be used for various display devices, various light sources, and the like.

It is a perspective view for demonstrating the manufacturing method of the organic electroluminescent element which concerns on this Embodiment. It is typical sectional drawing for demonstrating the organic material ejection hole formed in the convex part of the crucible of FIG. It is typical sectional drawing for demonstrating the organic material ejection hole formed in the convex part of the crucible of FIG. It is typical sectional drawing for demonstrating the organic material ejection hole formed in the convex part of a crucible. It is a schematic diagram which shows the positional relationship of the board | substrate of FIG. 1, and several crucibles. It is a typical structure figure of the organic EL element formed by the manufacturing method concerning this embodiment. It is a typical sectional view of a crucible. It is a schematic diagram which shows the positional relationship of a board | substrate and several crucibles.

Explanation of symbols

10, 11, 12 Crucible 20, 21, 22 Organic material ejection hole 50 Substrate 51 Anode (hole injection electrode)
52 hole injection layer 53 hole transport layer 54 light emitting layer 55 electron transport layer 56 cathode (electron injection electrode)
600 Organic EL device

Claims (3)

A method for producing an organic electroluminescence device comprising an organic layer made of an organic material on a substrate,
Filling at least two crucibles of a plurality of crucibles extending in a first direction and arranged substantially in parallel with the same organic material;
Heating the two crucibles;
And a step of moving the plurality of crucibles and the substrate relative to each other in a second direction intersecting the first direction. The plurality of crucibles eject the vapor of the organic material with a predetermined spread centering around a set ejection direction, and the at least two crucibles are ejected so that the organic material is deposited on a common region of the substrate. 2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the direction is set. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the organic material includes a rubrene-based material.

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